DaxiaoaixadDo you mean if we put the adverb in the front of the sentence, we should reorder the sentence? I have here another example:

* Juan hardly remembers the accident that took his sister's lifeSounds good.!! Hardly remembers Juan the accident that took his sister's lifeHardly does Juan remember..** Hardly Juan remembers the accident that took his sister's life.X

are they all the same? Or only one of !! and ** is correct? What is the general rule for that, I mean if the "reorder" of sentences?

Rule? I don't know. A more solid grammarian might answer that question. Perhaps we need an auxiliary verb to re-order sentences.

(EX) Never have so many people been unemployed as today.(EX) Hardly does Juan remember the accident that took his sister's life.These constructions are called "negative inversion". The rule is: when a negative adverb (like "never") or a quasi-negative adverb (like "hardly") is put at the head of a sentence (for the purpose of emphasis), the positions of the subject and the finite verb are inverted almost obligatorily.

Why do they such things? I don't know the exact reason. But I once heard that it is because English people can feel most relaxed when hearing or reading sentences where the finite verb is at the second position (V2 constructions).